Unhealthy Diets May Damage the Brain

Two powerful hormones, leptin and gherlin, are produced in the body and send signals to the area of the brain that regulates appetite. Both hormones activate the hypothalamus to achieve a balance between energy needs and food consumption.

But something happens in the brains of obese people to disrupt the balancing mechanism and interfere with their ability to lose weight and keep it off.

A new theory on obesity, published in the British Journal of Nutrition(BJN), suggests that the brain is actually damaged over time by eating fattening foods. The theory poses that simple carbohydrates like fructose and sucrose and saturated fats trigger an inflammatory response that actually damages the hypothalamus and renders it less sensitive to the hormones that are supposed to help it regulate hunger and fullness. The more obese the person, the more the signals seem to get messed up.

The net result is that signals of fullness may be confused with signals of hunger, leading to a never-ending cycle of hunger, weight gain and further damage to the appetite control center of the brain.

Ghrelin is secreted primarily in the lining of the stomach and increases hunger. When your stomach is empty and your belly starts to growl, ghrelin is signaling the hypothalamus that it’s time to eat.

Leptin is secreted primarily by the fat cells, but also the stomach, heart, placenta and muscle. Leptin decreases hunger by signally the hypothalamus that you’re full, and the more fat cells you have, the more leptin you produce in an effort to curb further weight gain. Obese people produce lots of leptin, but the brain somehow becomes resistant to the signal.

The BJN report indicates that fattening foods sends inflammatory cells to the hypothalamus and overloads the sensitive neurons, causing neurological damage that affects appetite control. The brain cells actually undergo transformation from the onslaught of inflammatory cells. These changes are called neurogenesis, leading to changes in brain structure.

Researchers from University of Liverpool offer some hope to those caught in the obesity–hunger cycle. While some damage to the brain from chronic overeating may be permanent, the rate of damage can be reduced by decreasing the intake of fatty foods. The type of diet isn’t as important as the need to cut calories.

The Liverpool researchers also looked at the impact of omega-3 fatty acids on brain health. Dietary fish oil from fatty fish such as salmon and mackerel appears to decrease some of the damaging effects of fattening foods.

So it’s possible that switching to a healthy, Mediterranean-type diet and taking omega-3 fatty acids can help reverse the hypothalamic damage. But don’t expect quick results. Rapid weight loss from severe dieting typically results in rapid regain of weight. And it can take years for the brain to restore a more normal response to hormonal messaging about hunger.

Committing to changing the quality and quantity of caloric intake is essential in order to heal the damage. The sooner you start, the better.